The demands of the modem workplace often leave an individual with little time at the end of the day for the preparation of a meal. Upon returning home, a working individual often does not want to spend time or effort in the kitchen preparing dinner.
Many potential solutions to these problems have been presented. For example, fast food and carry-out restaurants have proven to be quite popular. The individual can pick up his or her dinner on the way home from work. This solution suffers from the disadvantages, however, of a rather limited menu selection and the food is not palatable to many people. Furthermore, the food often gets cold by the time the person arrives home. Frozen meals or "TV dinners" have been around for a long time but, again, many people find that the taste of such prepackaged meals, often prepared weeks or months earlier, leaves a lot to be desired. In addition, maintaining an ample supply of the frozen meals requires excessive freezer space. A demand exists for an alternative approach to provide good quality meals that can be quickly prepared.
In response to this demand, a number of meal delivery services have been developed. These services offer restaurant-quality meals that are delivered frozen to the customer's home, regardless if the customer is home or not. As such, these services offer a high level of convenience for the customer. The services offer a menu with a wide selection of meal choices.
The frozen meals are left on a customer's doorstep in a container much in the same manner that milkmen of days past delivered milk. The containers include a source of refrigeration and are insulated so as to preserve the food in a frozen state. The customer, upon returning home, takes the frozen food out of the container, heats it in an oven and then enjoys a quickly prepared yet fresh tasting, delicious meal. The empty container is left on the customer's doorstep for replacement with a filled container by the delivery service the next day.
To maintain the delivered food in a frozen state, the containers used by the services must be insulated and include a source of internal refrigeration. The containers currently used feature foam insulation construction and contain gel packs filled with phase change material. In addition, high efficiency containers that are vacuum insulated and that use a minimal number of gel packs have recently been developed. Such a container is the subject of copending and commonly assigned U.S. patent application Ser. No. 08/886,669. Typically, the phase change material within the gel packs is packaged refrigerant gel that can be chilled to a temperature well below the freezing point of water. As such, frozen gel packs positioned within a container refrigerate food placed within the container.
Traditionally, the insulated containers used by delivery services have been prepared for use by placing the gel packs, and/or the containers themselves, in a walk-in freezer so as to freeze the phase change material and cool the containers to a desired temperature. A disadvantage of such an arrangement is that the gel packs take a long time to freeze. In addition, a large freezer space is required to prepare a sufficient number of containers. The required freezers for such an operation are expensive to purchase and use. Workers preparing the containers must also spend a significant amount of time within the freezers and thus suffer prolonged exposure to temperatures of around -18.degree. F. This results in increased worker discomfort, fatigue and potential illness.
Accordingly, it is an object of the present invention to provide a system whereby the phase change material within an insulated container may be quickly frozen to a predetermined temperature.
Another object of the present invention is to provide a system whereby the phase change material within an insulated container may be frozen to a predetermined temperature without the use of a large freezer.
Another object of the present invention is to provide a system whereby the phase change material within an insulated container may be frozen to a predetermined temperature with minimal labor.